Magnetizing Inrush Current Suppression via Phase-Controlled Circuit Breaker
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for suppressing magnetizing inrush current, such as using a circuit breaker with a resistor or measuring residual magnetic flux, are inefficient and cannot be applied to transformers that convert three-phase alternating-current voltage to single-phase alternating-current voltage, as they require additional components or cannot calculate magnetic flux effectively.
Innovation Solution
A magnetizing inrush current suppression apparatus that includes an interrupting phase detection unit, a single-phase alternating-current voltage measurement unit, and a closing unit to control the circuit breaker phase based on measured voltages, allowing for effective suppression of magnetizing inrush current in transformers that convert three-phase to single-phase voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If a circuit breaker with a resistor is used to suppress magnetizing inrush current, then the magnetizing inrush current is suppressed, but the whole size of the circuit breaker increases
Solution Approach 1:
The patent extracts the resistor component from the circuit breaker structure, implementing inrush current suppression through external resistance rather than integrating it into the breaker body. This allows the circuit breaker to suppress magnetizing inrush current without increasing its own size.
Solution Approach 2:
The patent introduces an external resistor as an intermediary element that mediates the inrush current suppression function. The resistor is connected in series with the circuit breaker during closing operation, allowing current limitation without being part of the breaker's permanent structure.
2Object-generated harmful factors
If residual magnetic flux measurement is used to control circuit breaker phase, then magnetizing inrush current is suppressed, but the method cannot be applied to three-phase to single-phase transformers
Solution Approach 1:
The patent changes the measurement parameter from residual magnetic flux to secondary voltage. This parameter change makes the method universally applicable to all transformer types including three-phase to single-phase transformers, as voltage measurement is straightforward regardless of transformer configuration or grounding system.
Solution Approach 2:
The patent substitutes the complex magnetic flux measurement system with a simpler voltage measurement system. By measuring secondary voltage and inferring the appropriate closing phase, the method avoids the complexity of direct magnetic flux measurement while achieving the same inrush current suppression effect.
3Object-generated harmful factors
If existing suppression methods are applied to three-phase to single-phase transformers, then additional components or complex calculations are required, but the patent's method avoids these requirements
Solution Approach 1:
The patent enables the circuit breaker to determine the optimal closing phase autonomously by measuring secondary voltage and detecting voltage zero-crossing points. This self-service approach eliminates the need for external magnetic flux measurement devices or complex calculation systems, making the solution simple and universally applicable.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The apparatus effectively suppresses magnetizing inrush current by determining the optimal phase for closing the circuit breaker, reducing voltage fluctuations and system disruptions, even in transformers that convert three-phase to single-phase voltage, without the need for additional components or complex magnetic flux calculations.
Implementation Method 1
a single-phase alternating-current voltage measurement unit for measuring the single-phase alternating-current voltage
Data Source
AI summary
According to one embodiment, there is provided a magnetizing inrush current suppression apparatus including an interrupting phase detection unit that detects a phase when the transformer that converts a three-phase alternating-current voltage to a single-phase alternating-current voltage is disconnected, a single-phase alternating-current voltage measurement unit that measures the single-phase alternating-current voltage on the power system side of the circuit breaker, and a closing unit that closes the circuit breaker in the detected phase, based on the measured single-phase alternating-current voltage.